Process of converting arylcarboxyamino-o-thioglycollic acids into hydroxythionaphthene compounds



Patented May 1931 ERWIN' HOFFA, OF .I-IOCHST-ONTHETMAIH,

trace Jan's Marinas, or HaNAu-oN-rrrn-MAIN,

AND FRITZ 'Ml 'LLER, OF HOGHST-ON-THE-MAIN, GERMANY, ASSIGNORS TO GENERAL ANILINE WORKS, INC., OF NEW YORK, N. Y., A CORPORATION OF DELAWARE rnocnss or CONVERTING ABYLcsnsoxraivrrnoorHIoeLYooLLro ACIDS INTO HY- nnoxrzrnronarnrrrnnn comrounps No Drawing. Application filed August 9, 1927, Serial No. 211,852, and in Germany April 16, 1927.

a suitable alkaline acting agent, particularly with caustic alkali solutions.

The new process proceeds probably according to the following scheme on I GONH20) alkalies somcooma Of particular interest is the procedure wherein X represents one ofthe substituents hydrogen and alkyl, and Y represents one of the substituents halogen and alkyloxy.

This new reaction is surprising, because it is known (see British specification No. 1117 3 of 1906), that the cyanaryl-o-thioglycollic acids (the'starting material for the carboxyamino-compounds) are. converted into amino- Accordlng thionaphthene-carboxylic acids. I to general assumption this reaction runs in such a way that the carboxyaminothiogly' collic acids are formed as intermediates and then split off water in statu nascendi.

ofoiNmm ONE: 7

The thus formed aminothionaphthene-carboxylic acids are very stable to alkaline acting agents and can only be converted advantageously into the corresponding hydroxythionaphthene compounds by treating them with dilute acids (of. Friedlander, Liebigs Annalen, Vol. 351, page 417) Our new process proves, that the above mentioned assump tion is erroneous. Our new process is adapt ed to the direct manufacture on a technical scale of. the hydroxythionaphthene compounds in an almost chemically pure state with an excellent yield. From th-esehydroxy- 'thionaphthene compounds the corresponding thioindigo dyestufis can be produced in the usual manner by oxidation Without previous ly isolating the hydroxythionaphthene. C0111? pounds.

In the present new reaction of conversion of arylcarboxyamino-o-thioglycollic acids into ring compounds, as described herein and as set forth in the followingclaims, it'is to be understood that we do not wish to limit ourselvesto theuse of an alkali as strictly defined. The same result will be produced and substantially thesame products obtained by-using alkaline sulfides, alkaline polysulfides, alkaline earths, such as milk of lime, any of which are in this process equivalents of alkalies.

I The following examples serve'to illustrate our invention but they are not intended to limit it thereto, the parts being parts by weight (1 245 parts of 1-1nethyl-5-chloroben zene-2-carboxyamino 3-thioglycollic acid of the probable formula V are dissolved in 4000 parts of water. and 54 parts of sodium carbonateand mixed with 180 parts ofacaustic soda. The solution is heated to 80 C. and kept at this temperature I CH3 separates which'is colored red by the color it ing-matterproduced atmospheric oziida-rhiq tion. By oxidizing the resulting hydroxythionaphthene and hydroxythionaphthene carboxylic acid respectively by means of one of the usual oxidizing agents the 4-l-dimethyl-6-6-dichlor-thio-indigo may be obtained without having previously to isolate the reaction product. V

(2) 10 parts of l-methyl-o-chlorobenzene- Q-carboxyamino-3-thioglycoilic acid are heated in a pressure-vessel for 5 hours to 140 C. with 100 parts of water and 30 parts of calcium hydroxide. The mass is filtered, while hot, and by oxidizing the solution the same dyestufli' as that produced according to Example (1) may be obtained without having previously to isolate the hydroxythionaphthene.

(3) 10 parts of l-methyl-5-chlorobenzene- 2-carboxyamino-3-thioglycollic acid are heated in a pressure-vessel for 5 hours to M0 C. with 100 parts of water and 50 parts of barium hydroxide. The further operations for obtaining the hydroxythionaphthene and the dyestufl therefrom may be carried out as indicated in Example (2).

(4.) 30 parts of crystallized sodium sulfide are melted at 90 C. Into this melt are introduced 10 parts of 1-n1ethyl-5-chlorobenzene- 2-carboxyainino-3-thioglycollic acid and the whole is heated to '90-100 C. until the evolution of ammonia has ceased. After the melt has cooled itis diluted with salt water and filtered by suction. By oxidizing the compound thus obtained the l-4J-dimethyl-6-6- thioindigo is obtained Without having previously to isolate the hydroxythionaphthene.

(5) 82 parts of 4c-ethoxybenzene1-car boxyamino-2-thioglycollic acid having the probable formula v o-mn W 4 2 are heated to 90 C. with 300-parts of caustic soda solution of 40 B. there are then added thereto 180 parts of water and the resulting pasty mass is heated for'one hour to 100 C.

The evolution of ammonia, which occurs during this operation, will have decreased at the conclusion of the time period. The whole is then dissolved in 3000 parts of water and by oxidizing the resulting solution the 6-6-diethoxythioindigo is obtained without having previously to isolate the 6-ethoxy-3- hydroxythionaphthene which has the probable formula on .ozmp

CO.NH2 (1) ary SCHQ-GOOH (2) while heating the reaction mixture.

2. The process which comprises causing an alkaline inorganic alkali forming metal compound to act upon an aqueous solution of a compound of the following general formula:

Y \S.CH2.COOH

wherein X represents hydrogen or alkyl vand Y stands for halogen or oxalkyl while heating the reaction mixture.

3. The process which comprises causing an alkaline inorganic alkali forming metal compound to act upon an aqueous solution of l-inethyl-5-chlorobenzene-Q-carboxyanrino-3- thioglycollic acid while heating the reaction mixture.

4. The process which comprises heating an aqueous solution of l-methyl-fi-chlorobenzene-Q-carboxyamino-3-thioglycollic acid in the presence of the hydroxide of an alkali or earth alkali metal to a temperature of about 140 C. in a closed vessel.

In testimony whereof, we affix our signatures.

EBVVIN HOFFA. JENS MULLER. FRITZ MULLER. 

